Facile vacancies engineering of CoFe-PBA nanocubes for enhanced oxygen evolution

Oxygen evolution reaction (OER) is known as the key for the large-scale production of hydrogen through electrochemical processes. Developing highly efficient OER electrocatalysts with well-defined structure remains a considerable challenge. Herein, a unique and facile Ar plasma treatment was introduced to modify cobalt iron Prussian blue analogs (CoFe-PBA) immobilized nickel foam (NF). The in situ generated carbon-nitrogen vacancies can effectively tune the local coordination environment and electronic structure of metal active sites in CoFe-PBA, thus improving the OER performance. The combination of CoFe-PBA and NF presents a 3D interworking network structure with highly exposed active sites and excellent electrical conductivity, guaranteeing stable and efficient OER process. The as-prepared electrocatalyst exhibited excellent OER performance with an overpotential of 256 mV at the current density of 50 mA cm−2 and a small Tafel slope of 39 mV dec−1. This work presents a facile strategy for the design and fabrication of highly efficient PBA-based OER electrocatalyst, and enriches our understanding of the structure-property relationship of the plasma-engineered electrocatalyst.